The construction of roadways and highways require that a considerable amount of material be removed to provide a road bed which is at a specific elevation so that the road bed neither climbs nor descends abruptly. This requires the removal of a considerable amount of material from the high places and depositing the material into the low places. Often the high places are located in rocky terrain and ordinary excavating machines are unable to economically remove the rocky material.
Sometime the rocky material is partially removed by blasting with explosives followed by bringing in suitable filling material so that a smooth road bed is achieved. Then the final road building material is applied to the bed.
Construction of road beds through mountains usually necessitates that the road bed be built adjacent to a shear cliff or vertical wall. Most rock removing machinery cannot make a cut at the base of a vertical wall for the reason that the apparatus that manipulates the digging teeth for excavating the rocky material usually is never as wide as the remainder of the machine. Accordingly, a stair-step series of cuts usually must be accepted when a road bed is constructed using prior art road building equipment.
It would be desirable to have made available a digging machine for planing a road wherein the digging machine includes a digging head thereon for digging in rocky terrain, and which can dig adjacent to a vertical wall. It would also be desirable that the digging machine forms a smooth road bed while removing the excavated material to a location away from the excavation. A digging machine of this type which can dig to a considerable depth and form an unusually smooth, wide road bed is the subject of the present invention.